1. Technical Field
The present invention relates to a device, status notification device, and more particularly, a device status notification device that has a function for notifying a status change when the status of the device changes.
2. Related Art
A usage form in which one printer is shared by a plurality of host computers by interconnecting the printer and the plurality of host computers through a network has been widely used. In such a usage form, each host computer needs to monitor the start or end of a print operation, a failure of the printer, or the like, by monitoring the status change in the printer. In order to allow the host computers to monitor such status change, a device status notification device is arranged on the printer side.
For example, when the network specification for interconnecting the printer and the host computers is TCP/IP, the printer can be monitored by using an SNMP (Simple Network Management Protocol). In other words, a management application complying with the SNMP is mounted on the host computer side, and a network interface complying with the same SNMP is mounted on the printer side. Then, the host computers monitor the printer status by using monitoring means of an SNMP Trap.
In addition, for a case where the predetermined status change occurs on the printer side, which host computer a status change is notified to is registered in advance in a notification destination information table that is arranged on the printer side. However, generally, there is a limit to the number of notification destination addresses that can be registered in the notification destination information table. Accordingly, when there is no vacancy in the notification destination information table in a case where a host computer that tries newly to start monitoring the printer attempts to register its notification destination address in the notification destination information table of the printer, the registration thereof cannot be made. When a notification destination address cannot be registered in the notification destination information table, the corresponding host computer cannot monitor the printer status.
On the other hand, there are cases where a notification destination that has been registered in the notification destination information table in advance but is not used anymore exists as the notification destination stops operating or is disconnected from the network. When such a notification destination that does not exist with validity is registered in the notification destination information table, it is not only that a new notification destination cannot be registered, but also notification of the status change is continuously transmitted to the notification destination based on the registration in the notification destination information table. Accordingly, unnecessary packets flow on the network, whereby the network load is increased.
Accordingly, for example, in JP-A-2003-99342, a technique for deleting a notification destination from the notification destination information table based on a deletion request from a management application of the host computer has been disclosed. However, according to this technique, the notification destination is deleted based on the deletion request from the management application, and accordingly, the management is responsible for the host computer side. Therefore, in a case where the host computer leaves out of the network without issuing the deletion request for some reason, the notification destination remains in the notification destination information table.
In addition, for example, in JP-A-2001-197059, a technique for arranging an effective period in each notification destination registered in the notification destination information table has been disclosed. However, when this technique is used, the effective period must be managed for each notification destination in the notification destination information table, and accordingly, the management of the notification destination information table becomes complicated.
In addition, such a problem is not limited to the printer and may occur in various types of devices other than the printer as long as the devices are device status notification devices that notify a notification destination of the status change.